A 100 kmol/h stream that is 97 mole% carbon tetrachloride (CCl4) and 3% carbon disulfide (CS2) is to be recovered from the bottom of a distillation column. The feed to the column is 16 mole% CS2 and 84% CCl4, and 2% of the CCl4 entering the column is contained in the overhead stream leaving the top of the column.

(a) Draw and label a flowchart of the process and do the degree-of-freedom analysis.

(b) Calculate the mass and mole fractions of CCl4 in the overhead stream, and determine the molar flow rates of CCl4 and CS2 in the overhead and feed streams.

(c) Suppose the overhead stream is analyzed and the mole fraction of CS2 is found to be significantly lower than the value calculated in Part (b). List as many reasons as you can for the discrepancy, including possible violations of assumptions made in Part (b).